| Action Fundraisers Limited | Pembroke | 2016 |
| Action Games Ltd | London | 2018 |
| Action Group for Ethiopians in Ealing | London | 1999 |
| Action Image Productions Ltd | Cheltenham | 2004 |
| Action Infinite Limited | Derby | 2021 |
| Action Information Technologies Limited | Oswestry | 1986 |
| Action Instincts Ltd | London | 2016 |
| Action League for Palestinians of Syria Ltd | London | 2014 |
| Action LEE Entertainment Ltd | London | 2020 |
| Action Links Ltd | London | 2024 |
| Action MAN Props Ltd | Motherwell | 2021 |
| Action Mann Limited | Barnsley | 2017 |
| Action Mirror Productions Ltd. | Abingdon | 2014 |
| Action Planning Limited | West Midlands | 1995 |
| Action Points Consulting Ltd | Poole | 2020 |
| Action Potential Ltd | Motherwell | 2005 |
| Action Printers Ltd | York | 2008 |
| Action Productions Ltd | Sale | 2014 |
| Action Profits Ltd | London | 2022 |
| Action Projects Limited | Ware | 1996 |
| Action Props Ltd | Liverpool | 2024 |
| Action Publishing Technology Limited | Gloucestershire | 1981 |
| Action Replay Limited | London | 2018 |
| Action Rigging Ltd | Braintree | 2018 |
| Action Shack Limited | London | 2019 |
| Action Shots Limited | Barnet | 2011 |
| Action Special Effects Ltd | Camberley | 2023 |
| Action Sports TV Limited | Norwich | 2011 |
| Action Starter Limited | Birmingham | 2012 |
| Action TEC Services Midlands Ltd | Swadlincote | 2003 |
| Action Time Limited | Royston | 2015 |
| Action Traction Limited | Bedfordshire | 2006 |
| Action Trauma Limited | Ballynahinch | 2017 |
| Action Venture Capital Ltd | London | 2014 |
| Action Ventures Limited | Warwick | 2020 |
| Action Wealth Publishing Limited | London | 2018 |
| Action Xtreme Ltd | Lancaster | 2019 |
| Actionability Limited | Harbury | 2002 |
| Actionable Business Limited | Glasgow | 2002 |
| Actionable Data Intelligence Limited | Mediacityuk | 2020 |
| Actionable Data Solutions Ltd | London | 2025 |
| Actionable Insight Digital Marketing Limited | Westbury | 2011 |
| Actionable Intelligence Ltd. | Nottingham | 2014 |
| Actionable Ltd | London | 2021 |
| Actionable Research Ltd | London | 2018 |
| Actionable Software Ltd | London | 2021 |
| Actional AI Ltd | Ruislip, | 2025 |
| Actionary Ltd | Chalgrove | 2023 |
| Actioncom Limited | Middlesex | 1991 |
| Actioncy Tech Ltd | London | 2019 |
| Actiondisk Limited | Southsea | 1988 |
| Actionflux Limited | Stroud | 1988 |
| Actionfunder Ltd. | London | 2005 |
| Actiongen Limited | London | 2024 |
| Actiongo Ltd | Kington | 2025 |
| Actiongolden Limited | Braintree | 1996 |
| Actionhouse Limited | Welling | 2026 |
| Actionone Limited | Southport | 2022 |
| Actionpoint Solutions Limited | Surrey | 1999 |
| Actionscript Solutions Ltd | Carnforth | 2008 |
| Actionsmartai Ltd | London | 2025 |
| Actionsolve Limited | Derby | 2023 |
| Actionstar.Ai Limited | London | 2026 |
| Actionstep Operations UK Limited | High Wycombe | 2017 |
| Actionstream Direct Media Limited | Hereford | 2000 |
| Actiontactic Limited | Basildon | 1996 |
| Actionwest Business Systems Limited | Kingsbridge | 1997 |
| Actionzz Limited | Plymouth | 2015 |
| Actipath Limited | Ferndown | 2017 |
| Actiphons Limited | Manchester | 2016 |
| Actis Sales Technologies Limited | Marlow | 1999 |
| Actismedia.Co.Uk Limited | Nottingham | 2014 |
| Actisoft Technology Limited | London | 2017 |
| Actisys Limited | Cardiff | 2019 |
| Actito UK Limited | London | 2019 |
| Actium Labs Ltd | Cowes | 2026 |
| Actium Online Ltd | Belfast | 2025 |
| Activ App Ltd | London | 2025 |
| Activ Business Solutions Ltd | Amersham | 2017 |
| Activ Educate Ltd | Swindon | 2007 |
| Activ Emea Ltd | London | 2012 |
| Activ Ingredient Solutions Limited | Dukinfield | 2022 |
| Activ Intelligent Ltd | London | 2024 |
| Activ Ltd | London | 2024 |
| Activ OPS Solutions Ltd | Leicester | 2016 |
| Activ-Ai Ltd | London | 2024 |
| ACTIV8 Computer Solutions Limited | Hampshire | 2003 |
| ACTIV8 Global (UK) Ltd | Southsea | 2024 |
| ACTIV8 Information Security Limited | Bristol | 2010 |
| ACTIV8 Intelligence Limited | Redditch | 2005 |
| ACTIV8 IT Support Ltd | Plymouth | 2019 |
| ACTIV8AI Ltd | Peterborough | 2025 |
| ACTIV8CONNECT Ltd | Lymm | 2026 |
| Activaeon Limited | Gateshead | 2004 |
| Activait Technology Limited | Banbury | 2023 |
| Activaite Limited | London | 2015 |
| Activate & Barrel Ltd | London | 2025 |
| Activate Business Systems Limited | Wirral | 1998 |
| Activate Capital Limited | London | 2016 |
| Activate Computers Limited | Frizington | 2011 |